Low-Temperature Roll-to-Roll Atmospheric Atomic Layer Deposition of Al₂O₃ Thin Films

Abstract

The Al2O3 thin films deposition through conventional ALD systems is a well-established process. The process under low temperatures has been studied by few research groups. In this paper, we report on the detailed study of low-temperature Al2O3 thin films deposited via a unique in-house built system of roll-to-roll atmospheric atomic layer deposition (R2R-AALD) using a multiple-slit gas source head. Al2O3 thin films have been grown on polyethylene terephthalate substrates under a very low-temperature zone of room temperature to 50 °C and working pressure of 750 Torr, which is very near to atmospheric pressure (760 Torr). Al2O3 thin films with superior properties were achieved in the temperature range of the ALD window. An appreciable growth rate of 0.97 Å/cycle was observed for the films deposited at 40 °C. The films have good morphological features with a very low average arithmetic roughness (Ra) of 0.90 nm. The films also showed good chemical, electrical, and optical characteristics. It was observed that the film characteristics improve with the increase in deposition temperature to the range of the ALD window. The fabrication of Al2O3 films was confirmed by X-ray photoelectron spectroscopy (XPS) analysis with the appearance of Al 2p, Al 2s, and O 1s peaks at the binding energies of 74, 119, and 531 eV, respectively. The chemical composition was also supported by the Fourier transform infrared spectroscopy (FTIR). The fabricated Al2O3 films demonstrate good insulating properties and optical transmittance of more than 85% in the visible region. The results state that Al2O3 thin films can be effectively fabricated through the R2R-AALD system at temperatures as low as 40 °C.

Low-temperature remote plasma enhanced atomic layer deposition of ZrO2/zircone nanolaminate film for efficient encapsulation of flexible organic light-emitting diodes

“…On the other hand, the peak of CH 3 is stronger than the Zr–O–Zr peak. Clearly, the reaction occurs more readily with increasing temperature34.…”

High-Performance, Air-Stable, Low-Temperature Processed Semitransparent Perovskite Solar Cells Enabled by Atomic Layer Deposition

“…42,43 The viability of ALD in high-throughput roll-to-roll compatible process has also been demonstrated recently. [44][45][46] Con-sidering the unique capabilities afforded by ALD-high quality film and large area/large batch deposition with low deposition temperature, we envision that ALD can potentially offer a manufacturing-friendly and costeffective solution to the development of the PSC technology. Despite these attractive advantages, only very few studies have dedicated so far to integrating ALD-growth thin films into PSCs, and only moderate PCEs are achieved (<13%).…”

Transparent Aluminium Oxide Coatings of Polymer Brushes

“…It can be part of electric devices due to its high dielectric constant ( ɛ r ≈9), or used as an environmental protective coating thanks to its thermal resistance . Moreover, alumina ceramics have been successfully used as parts of lamps because of their high optical transmittance . Concerning the polymer substrates, grafted‐from polymer brushes have been established as stimuli‐responsive coatings .…”

“…Such a limitation has prompted the research on new synthetic protocols, which may allow to produce alumina under mild conditions. Some recent examples in literature illustrated the possibility of producing Al 2 O 3 thin films by using lower temperature atomic or chemical layer deposition, but the most prominent improvement in this field was made with the introduction of low‐temperature sol‐gel methods to produce either crystalline or amorphous Al 2 O 3 thin films from organic or aqueous solutions and harmless chemicals.…”